“It’s going to be a clear three-way race,” said Martin Horak, head of Western University’s local government program. “It’s going to be a fascinating race to watch.”

Horak believes Swan will especially eat into Caranci’s support.

For months, Swan has mulled two options: Moving up — leaving his ward seat to run for mayor — or moving out, and leaving council altogether.

Tuesday, he declined to directly address the media speculation his scheduled 4 p.m. event Wednesday will be a mayoral campaign launch.

“I think I’ll be respectful of my volunteers and make the announcement as I’ve promised,” Swan said.

“It’ll certainly give a direction for my involvement in the direction of the (next) council.

“I’m looking forward to a very invigorating campaign of ideas for the future of London.”

Invigorating, certainly.

But it could be a tough road, too.

Swan, who served on council from 1988 to 2003, earned the sobriquet “the Corley Drive socialist” and ran federally in 2004 for the NDP. His return to council in 2010, though, brought a much different tone.

He’s positioned himself as a job-creating champion of business and closely aligned himself with Joe Fontana, the mayor who recently resigned in disgrace following his criminal convictions.

That link to Fontana could prove tough to shake on the campaign trail. It may affect Swan’s “credibility,” as Horak noted. He’s also linked to a proposed concert hall, which has become a controversial issue.

But Swan also brings strengths to the race. He could position himself as the candidate with the experience to lead London, particularly compared to Brown, who’s a council rookie.

This fall will mark the first time in nearly 15 years London has had a mayoral race without an incumbent. There are 12 candidates, with the Big Three the clear favourites.

Which one of them will win? That’s anyone’s guess at this point, Horak says.

“I think every one of these candidates has certain weaknesses that the other candidates can point to,” he said. “This isn’t anybody’s race to lose.”